I received request for information on adding brake controller wiring to a RAV4. Since I've done this, as well as adding a charge line from the battery
to the 7 pin hitch connector, I thought I'd post this for others. It probably makes sense to do this when adding the trailer light
kit (Even though Toyota calls it a "Tow Package", it doesn't include the hitch or trailer light
wiring, at least in the US).
Toyota recommends not tapping into the brake/tail light
wiring, possibly because they use LED lighting
& the wiring and fusing may no be heavy enough. For what ever reason, they have a wiring harness that provides a 4 way trailer plug at the rear of the vehicle, and runs to a socket under the dashboard. Unless you are a contortionist, finding & plugging into this socket is a challenge! By the way, I have also seen plug in versions of trailer wiring kits by after market suppliers that don't require running to the socket under the dash, so I guess it can be done.
I pretty much followed this web page
. I used #10 wire for the charge line & #12 for the brake line. They are wired through a 30 amp & 20 amp circuit breaker. The run from the battery
to the pair of breakers under the passenger side dash was made with #6 wire & a 50 amp fuse. If you have a 3 way refrigerator
& plan on running it on DC while traveling, you might consider #8 wire for the charge line - the less voltage drop between the tow vehicle alternator & the trailer's battery
, the better charging current you will get. It would be a good idea to insure that the ground wiring is also at least #10 or better since both carry the same current. While some feel you can depend on the ground connection through the framer of the tow vehicle & trailer, I'd prefer copper wire.
It took a full day to do the project - much of the time was spent finding a place for & mounting a 50 amp fuse in the engine compartment & removing the driver's side trim for the run between the front & rear of the vehicle.
I also added a isolation relay in the jack storage area so the charge line would be shut off when ever the ignition of the RAV4 was off. This will prevent running the vehicle battery down when parked for lunch, etc (it doesn't prevent the trailer's battery from discharge, so it would be wie to switch to propane
if you are making a long stop). The sense wire for the relay was powered by the 12V outlet in the same compartment.
O course, all this is only useful for 2012 and older RAV4s - Toyota dropped the V6 & trailer package with the 2013 models.